Mercury boiler



L. R. BIGGS MERCURY BOILER Dec. 26, 1939.

Filed Jan. 3

M l ------I----l\ 11-11512:

Inventor" Lenard R. Bi

H is Att oTT-ley.

Patented Dec. 26, 1939 MERCURY :corunar Leonard R. Biggs, Schenectady, N; Y., assignor to General Eiectric Company, a, corporation of v New York l application January 3, 193s, serial No. 182,979l

3 Claims.

rIvhe present invention relates to mercury boilers, that is, to arrangements comprising heating elements for containing mercury liquid to be heated and evaporated.

The object of my invention is to provide an improved constructionand arrangement of mercury boilers which may be operated efciently and economically.

l For a consideration of what I believe to be lo novel and my invention, attention is directed to the following description and they claims appended thereto in connection with the accompanying drawing.

- In the drawing, Fig. l represents a perspective Y.

view partly broken away. of a mercury boiler embodying my invention, and Fig. 2 illustrates a detail view of a part of Fig. 1. y

The boiler has side walls l 9 and rear and front walls il, the lower wall portions defining a ccmbustion chamber l2 and the upper wall portions dening a convection chamber or space la Combustible material, for instance pulverized coal, is

burned in the combustion space and the comf bustion gases flow through the convection space into a flue, not shown. The inner surfaces of the walls are lined with heating elements i4 and i5. Each element has a plurality of tubes l5 embedded in copper or other material of good heat conductivity to effect good heat transmission to 8 0- the tubes and the mercury co-ntained therein. The upper ends of the tubes it of each element are united into single tubes il. Whereas the heating elements l5 lining the rear wall and the front wall (not shown) cover said wall in both the combustion space and the convection space, the elements lll cover the side walls only within the combustion space. The lower ends of the tubes of the heating elements Hi, l5 are connected to a lower header IS. As shown in the 401 drawing, the individual tubes It are connected to the top portion of the header and short, sealed tubes l forming in substance extensions of the tubes I6 are connected to the bottom portion of the header tol facilitate cleaning of the tubes IS whenever this is necessary. Mercury liquid is conducted to the lower header i8 by a plurality of conduits 223 which in turn are connected through conduits 2i and 22 to a cylindrical drum or vessel 23 centrally located in the upper portion of the convectionspace I3 and projecting through the rear wall i i Mercury liquid is supplied to the drum from a condenser or other source, not shown, through an inlet conduit 2t which has a portion extending within the drum throughout the entire length thereof. This portionl has a plurality of openings or orices 25 for uniformly supplying mercury throughout the length of the drum and thus to maintainuniform the operating substance which in addition to the mercury ,may include small amounts of sodium, aluminum, titanium, zirconium or other substances. 23 through a conduit 26. The drum also includes liquid vapor separating means in the form of a V-shaped perforated wall 2l disposed in the vapor space of the drum. The conduits il have a cross section which increases in the direction of flow to take care of the increase involume of the operating substance due to evaporation thereof. The end portions of the conduit il are connected to the` drum 23 above the mercury contained therein Yand below the liquid vapor separating wall 2l.4

Thelower portions of the heating elements lll, l5 are covered with refractory material 28 to protect these portions :from vthe `intense heat in the combustion space.

The convection space of the boiler is lled with a pluralityV of `banks of vadditional heating tubes forming large surfacesl to which heat is trans'- mitted by convection. More specifically, I provide lower banks of heating tubes and upper Vapor is discharged from the drum banks of heating tubes, which latter have a length K about twice that of the lower banks. In the present instance the arrangement comprises lower banks of heating tubes ligand 3G and upper banks of heating tubes 3| and 32 symmetrically arranged with regard to a vertical vplane through the center of the drum 2l. Mercury liquid is supplied to the banks of heating tubes by down-y n comers 33 connected to the bottom portion of the drum 2'1. The lower bank 29 has a lower header 34 and an upper header 35 connected by rowsof tubes 36 and 3l. The ends of the tubes 36 and .'57, as shown in Fig. 2, are bent` inward and secured to the inner surfaces of the headers 'Sli and 35- by welds-SS and 39 respectively. T'o this end the headers 3Q and 35 are made of two segmental portions 'lll and @il united by fused metal or welds 2. During manufacture the tubes 36 and 3l are bent ,and welded to the segmental portions lil of the lower and upper headers whereupon the other segmental portions @I of said headers `are welded yto the portions 4Q.

The righthand ends of the headers 34 Aand 35 of the bank of heating tubes 29 are connected to the down-tube 33 and the lefthand ends of the headers 34 and 35 are connected to'the'up-tube l1 so that the latter forms a-portion of the wall heating elements and of the heating elements formed by the bank of tubes in the convection space. The lower bank of tubes 30 has lower and upper headers 43 and 44 connected at their lefthand ends to the down-tube 33 and at their righthand ends to an up-tube 45 forming a part of the wall heating tubes covering the righthand side wall of the boiler. The upper and lower headers of the banks 29 and 30 slant upwardly from their common down or supply tube 33. During operation mercury is supplied to the down-tube, whence it iiows through said headers and the tubes connected between them into the wall tubes l and 45 respectively.

The upper banks of tubes in the convection surface are similarly arranged and co-mprise lower headers 46 and upper headers [il with a plurality of tubes 48 connected between them. These headers with regard to the bank 3i are connected between the down-tube 33 and the up-tube H and with regard to the bank 32 the headers are connected between the down-tube 33 and the up-tube 45.

With my invention I have accomplished an improved construction and arrangement of mercury boilers which requires comparatively small floor space and in which the heat in the convection space is effectively utilized. The boiler in accordance with my invention as shown in the drawing comprises a single drum to which mercury is conducted so that any chemicals or other substances contained in the mercury will remain thoroughly mixed therewith. The heating units comprise wall tubes or heating elements lining the walls and banks of tubes uniformly distributed in the convection space and interconnected with the upper portions of the wall tubes. Mixture of mercury and vapor formed in the tubes is conducted to the drum near the top thereof and mercury liquid is conducted to the heating cold liquid level within the upper portion of the tubes 36, 31 of the lower bank of tubes 29 and 30. During operation the mercury due to heat expands and thus causes the upper banks of tubes gradually to become filled. In case the boiler is operated together with a turbine and a condenser the mercury may be conducted from the condenser directly into the drum without first being preheated in a preheater. The lower banks of tubes 29, 30 being disposed near the hot zone are made of comparatively short tubes located considerably below the drum to reduce evaporation of the mercury therein.

Having described the method of operation of my invention, together with the apparatus which I now consider to represent the best embodiment thereof, I desire to have it understood that the apparatus shown is only illustrative and that the invention may be carried out by other means.

What I claim as new and desire to secure by Letters Patent of the United States is:

l. Mercury boiler comprising the combination of front, rear and side walls with lower wall portions forming a combustion space and upper wall portions forming a convection space, a liquid vapor separating drum disposed in the upper portion of the convection space, heating elementslining the inner surfaces of the walls in the combustion space and having individual extensions independent of each other and lining the wall in the convection space with discharge ends connected to the drum, and banks of heating tubes disposed within the convection space and connected to receive mercury liquid from the drum and to discharge mercury liquid and vapor into said extensions.

2. Mercury boiler comprising the combination of walls forming a combustion space and a convection space, heatingv elements comprising a plurality of tubes lining the walls, a drum connected to the discharge ends of the heating elements, conduit means for conducting mercury from the drum to the lower ends of the heating elements, lower and upper banks of tubes disposed within the convection space with each bank having a lower and an upper header, and conduit means for conducting mercury liquid from the drum to the headers, said headers being arrangedto discharge mixture of mercury liquid and vapor formed therein into upper portions of the wall heating elements. v

3. Mercury boiler comprising the combination of walls, heating elements lining the walls and forming a combustion space and a convection space, a cylindrical drum horizontally disposed in the upper portion of the convection space and projecting through one of said walls, a conduit projecting into the drum and extending along the entire length ,thereof and having a plurality of orifices for conducting mercury liquid to the drum, means including a down-tube connected to the bottom of the drum for conducting mercury liquid from the drum to the lower ends of the heating elements, said elements having discharge ends connected to upper portions of the drum, a plurality of lower and upper banks of heating tubes disposed within the convection space and symmetrically arranged on opposite sides of a vertical plane through the drum, each bank having an upper and a lower header with a plurality of vertically arranged tubes connected between the hea-ders, said headers being inclined and having their upper ends connected to the heating elements, and conduit means for conducting mercury liquid to the lower ends of said inclined headers.

LEONARD R. BIGGS. 

